Credit

Caption

Cross section of the Milky Way galaxy. Computer artwork of the Milky Way galaxy, which contains our solar system, with a slice removed (bottom left) to reveal its internal structure. The Milky Way is a spiral galaxy. It has a central bulge (yellow) of old stars that has a bar (white) of older, redder stars passing through it. The galactic bar is thought to act like a propeller inside the centre, giving our galaxy its spiral shape. Around this nucleus, 10,000 to 16,000 light years away, is a bright 'molecular ring' (blue) of young hot stars and star forming regions. The spiral arms extend outwards from this ring. The total diameter of the galaxy is thought to be 100,000 light years.